Moisture Management and Transport Cover
An occupant support (20) includes an intermediate layer (26, 30, 120) and a wicking layer (52) atop the intermediate layer. The wicking layer comprises a first region (62) having a lower moisture wick rate (W1) and a second region (64) having a higher wick rate (W2). A moisture management cover (52) for use with an occupant support article has discrete higher (64) and lower (62) wick rate regions. A related method for transporting moisture away from a target region of an occupant support comprises distributing the moisture over an area beyond area A and exposing the distributed moisture to a fluid stream capable of receiving the moisture.
The subject matter described herein relates to a cover for enhanced in-plane moisture transport. One example application for the cover is on a hospital bed where it may be used in conjunction with a microclimate control topper or as a stand alone mattress cover to help transport moisture away from a region underneath an occupant of the bed thus achieving better control of moisture on the occupant's skin.
BACKGROUNDLong term occupants of beds, such as patients confined to a hospital bed, are at risk of skin breakdown. Such risks are exacerbated by excessive moisture on the occupant's skin. Frequently the source of the moisture is the occupant's own perspiration. One known way to control moisture in contact with the occupant's skin is to place a microclimate control (MCC) topper between the mattress and the occupant. A typical MCC topper comprises a vapor permeable top side and a bottom side. The sides define an interior cavity having an air inlet and an air outlet. The interior cavity serves as a flowpath for ambient or conditioned air. In operation, a blower propels a stream of air through the flowpath. Occupant perspiration, specifically the gaseous phase of the perspiration, enters the flowpath through the vapor permeable top side. The ambient or conditioned air flowing through the flowpath carries the moisture away. The flowpath thus serves as a moisture sink for moisture in contact with the occupant's skin.
Although MCC toppers are effective, their effectiveness is limited by the fact that the source moisture is mostly present in a confined area immediately underneath the occupant. Only those portions of the air stream directly under the moist area are effective at removing the moisture. As a result some of the moisture removal capacity of the topper is unused.
SUMMARYOne embodiment of an occupant support includes an intermediate layer defining at least part of a fluid flowpath and having a vapor permeable occupant side. The occupant support also includes a wicking layer atop the intermediate layer. The wicking layer comprises a first region having a first moisture wick rate and a second region having a second moisture wick rate that exceeds the first moisture wick rate. A moisture management cover described herein is cooperable with an occupant support article having an occupant support side so that the occupant support side and an opposing portion of the cover define a fluid flowpath. The cover has discrete higher and lower wick rate regions. A related method for transporting moisture away from a target region of area A of an occupant support comprises distributing the moisture over an area beyond area A and exposing the distributed moisture to a fluid stream capable of receiving the moisture.
The foregoing and other features of the various embodiments of the moisture transport cover described herein will become more apparent from the following detailed description and the accompanying drawings in which:
Referring to
The microclimate control topper 30 has a vapor permeable top or occupant side 36, whose longitudinal and lateral dimensions are D1, D2, a bottom side 38, and an air permeable spacer 40 between the sides. The occupant and bottom sides 36, 38 define a fluid flowpath 42 extending longitudinally substantially the length L of the topper. The topper has an inlet 46 and an outlet 48. A blower, not shown, propels a stream of air 50 through the flowpath. In operation, the occupant's perspiration, after having transitioned to the gaseous phase, passes through the vapor permeable occupant side 36 and enters the air stream 50. The air stream carries the moisture away through outlet 48. In the embodiment of
The occupant support also includes a moisture management cover or wicking layer 52, atop the intermediate layer. At least part of the wicking layer is made of a material exhibiting a high in-plane moisture transport rate, referred to herein as a wick rate. Examples of materials having high wick rates include polypropylene, Meryl Skinlife®, SORBTEK™, and Poro-Tex expanded PTFE (ePTFE). The wicking layer of
The illustrated wicking layer comprises a first region 62 having a first moisture wick rate W1 and a second region 64 having a second moisture wick rate W2 that exceeds the first moisture wick rate. In one embodiment the longitudinal borders of region 64 are laterally extending border 91 located approximately at the occupant's scapula and border 92 located at about mid-thigh. In another embodiment the borders are border 93 at about midway along the occupant's back and 94 at about the occupant's buttocks. First region 62 is a perimetrical region that laterally and longitudinally bounds second region 64. The second region extends laterally beyond the approximate outline 66 of a supine occupant of the bed. The high wick rate of second region 64 spatially distributes the occupant's perspiration more readily than would be the case if the wick rate were lower. In particular the high wick rate of region 64 spreads the perspiration beyond the outline 66 of the occupant. More moisture is therefore exposed to air stream 50 resulting in better use of the moisture removal capacity of the topper and an attendant increase in moisture removal from the occupant's skin. Nevertheless, it is also contemplated that a high wick rate that does not extend laterally beyond the occupant could be beneficial.
The wicking layer illustrated in
Wick rate W2 may be spatially nonuniform, i.e. the wick rate need not be constant in any given direction. In addition the wick rate, even if constant in any given direction, need not be the same in one given direction as in another given direction. For example it is envisioned that wick rate W2 could have a value W2LONG in the longitudinal direction and a different, higher value W2LAT in the lateral direction, with at least W2LAT being greater than first wick rate W1. Because most occupants are taller than they are wide, the higher wick rate in the lateral direction can quickly transport moisture beyond the left and right edges 74, 76 of the occupant outline 66 where that moisture will be exposed to the drying effects of ambient air in addition to being acted on by the internal air stream 50. The higher lateral wicking rate is therefore believed to be more efficacious than a higher longitudinal wicking rate.
In
In the variants of
Although the embodiments disclosed herein have a first region with a lower wick rate and a second region with a higher wick rate, more than two regions each having individual, customized wick rates can be used.
The terms “wicking” and its variants, as used herein to describe the moisture management cover, are intended to convey the notion of moisture transport in the plane of the cover and are not to be interpreted as limited to any particular physical mechanism of moisture transport.
Although this disclosure refers to specific embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made without departing from the subject matter set forth in the accompanying claims.
Claims
1. An occupant support comprising:
- a intermediate layer defining at least part of a fluid flowpath and having a vapor permeable occupant side; and
- a wicking layer atop the intermediate layer, the wicking layer comprising a first region having a first moisture wick rate and a second region having a second moisture wick rate that exceeds the first moisture wick rate.
2. The occupant support of claim 1 wherein the first region is a perimetric region that bounds the second region.
3. The occupant support of claim 1 wherein the wicking layer is in the form of a fitted sheet.
4. The occupant support of claim 1 wherein the second wick rate comprises longitudinal and lateral wick rates at least the lateral one of which is greater than the first wick rate and the lateral wick rate exceeds the longitudinal wick rate.
5. The occupant support of claim 1 wherein the second region is nonrectangular.
6. The occupant support of claim 1 wherein the wicking layer is removably attached to the intermediate layer.
7. The occupant support of claim 1 wherein the wicking layer is nonremovably attached to the intermediate layer.
8. The occupant support of claim 1 wherein the wicking layer comprises a material bonded to the intermediate layer by a vapor permeable adhesive.
9. The occupant support of claim 1 wherein the wicking layer is a vapor permeable coating.
10. The occupant support of claim 1 wherein the wicking layer is integrated into the intermediate layer.
11. The occupant support of claim 1 wherein the wick rate of the second region is nonuniform.
12. The occupant support of claim 1 wherein the intermediate layer is a microclimate control topper.
13. A moisture management cover, the cover being cooperable with an occupant support article having an occupant support side so that the occupant support side and an opposing portion of the cover define a fluid flowpath, the cover having discrete higher and lower wick rate regions, the higher wick rate region having a higher moisture wick rate than that of the lower wick rate region.
14. The moisture management cover of claim 13 wherein the higher wick rate region is a perimetral region that bounds the lower wick rate region.
15. The moisture management cover of claim 13 wherein the cover is in the form of a fitted sheet.
16. The moisture management cover of claim 13 wherein the higher wick rate comprises longitudinal and lateral wick rates at least the lateral one of which is greater than the lower wick rate and the lateral wick rate exceeds the longitudinal wick rate.
17. The moisture management cover of claim 13 wherein the higher wick rate region is nonrectangular.
18. The moisture management cover of claim 13 wherein the wicking layer is removably attachable to a intermediate layer.
19. The moisture management cover of claim 13 wherein the higher wick rate region comprises a material bonded to the intermediate layer by a vapor permeable adhesive.
20. The moisture management cover of claim 13 wherein the wicking layer is a vapor permeable coating.
21. The moisture management cover of claim 13 wherein the wick rate of the higher wick rate region is nonuniform.
22. A method for transporting moisture away from a target region of an occupant support, the region having an area A, the method comprising:
- distributing the moisture over an area beyond area A; and
- exposing the larger area to a fluid stream capable of receiving the moisture
23. The method of claim 22 wherein the area beyond area A is laterally beyond area A.
Type: Application
Filed: Sep 23, 2011
Publication Date: Mar 28, 2013
Inventors: Charles A. Lachenbruch (Lakeway, TX), Christopher R. O'Keefe (Batesville, IN), Timothy J. Receveur (Guilford, IN), Rachel Williamson (Batesville, IN)
Application Number: 13/241,693
International Classification: A47C 17/00 (20060101); A47G 9/02 (20060101);